// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/nix/xdg_util.h"

#include <string>

#include "base/base_paths.h"
#include "base/environment.h"
#include "base/files/file_path.h"
#include "base/files/file_util.h"
#include "base/path_service.h"
#include "base/third_party/xdg_user_dirs/xdg_user_dir_lookup.h"

namespace {

// The KDE session version environment variable introduced in KDE 4.
const char kKDESessionEnvVar[] = "KDE_SESSION_VERSION";

} // namespace

namespace base {
namespace nix {

    const char kDotConfigDir[] = ".config";
    const char kXdgConfigHomeEnvVar[] = "XDG_CONFIG_HOME";

    FilePath GetXDGDirectory(Environment* env, const char* env_name,
        const char* fallback_dir)
    {
        FilePath path;
        std::string env_value;
        if (env->GetVar(env_name, &env_value) && !env_value.empty()) {
            path = FilePath(env_value);
        } else {
            PathService::Get(DIR_HOME, &path);
            path = path.Append(fallback_dir);
        }
        return path.StripTrailingSeparators();
    }

    FilePath GetXDGUserDirectory(const char* dir_name, const char* fallback_dir)
    {
        FilePath path;
        char* xdg_dir = xdg_user_dir_lookup(dir_name);
        if (xdg_dir) {
            path = FilePath(xdg_dir);
            free(xdg_dir);
        } else {
            PathService::Get(DIR_HOME, &path);
            path = path.Append(fallback_dir);
        }
        return path.StripTrailingSeparators();
    }

    DesktopEnvironment GetDesktopEnvironment(Environment* env)
    {
        // XDG_CURRENT_DESKTOP is the newest standard circa 2012.
        std::string xdg_current_desktop;
        if (env->GetVar("XDG_CURRENT_DESKTOP", &xdg_current_desktop)) {
            // Not all desktop environments set this env var as of this writing.
            if (xdg_current_desktop == "Unity") {
                // gnome-fallback sessions set XDG_CURRENT_DESKTOP to Unity
                // DESKTOP_SESSION can be gnome-fallback or gnome-fallback-compiz
                std::string desktop_session;
                if (env->GetVar("DESKTOP_SESSION", &desktop_session) && desktop_session.find("gnome-fallback") != std::string::npos) {
                    return DESKTOP_ENVIRONMENT_GNOME;
                }
                return DESKTOP_ENVIRONMENT_UNITY;
            } else if (xdg_current_desktop == "GNOME") {
                return DESKTOP_ENVIRONMENT_GNOME;
            } else if (xdg_current_desktop == "KDE") {
                std::string kde_session;
                if (env->GetVar(kKDESessionEnvVar, &kde_session)) {
                    if (kde_session == "5") {
                        return DESKTOP_ENVIRONMENT_KDE5;
                    }
                }
                return DESKTOP_ENVIRONMENT_KDE4;
            }
        }

        // DESKTOP_SESSION was what everyone used in 2010.
        std::string desktop_session;
        if (env->GetVar("DESKTOP_SESSION", &desktop_session)) {
            if (desktop_session == "gnome" || desktop_session == "mate") {
                return DESKTOP_ENVIRONMENT_GNOME;
            } else if (desktop_session == "kde4" || desktop_session == "kde-plasma") {
                return DESKTOP_ENVIRONMENT_KDE4;
            } else if (desktop_session == "kde") {
                // This may mean KDE4 on newer systems, so we have to check.
                if (env->HasVar(kKDESessionEnvVar))
                    return DESKTOP_ENVIRONMENT_KDE4;
                return DESKTOP_ENVIRONMENT_KDE3;
            } else if (desktop_session.find("xfce") != std::string::npos || desktop_session == "xubuntu") {
                return DESKTOP_ENVIRONMENT_XFCE;
            }
        }

        // Fall back on some older environment variables.
        // Useful particularly in the DESKTOP_SESSION=default case.
        if (env->HasVar("GNOME_DESKTOP_SESSION_ID")) {
            return DESKTOP_ENVIRONMENT_GNOME;
        } else if (env->HasVar("KDE_FULL_SESSION")) {
            if (env->HasVar(kKDESessionEnvVar))
                return DESKTOP_ENVIRONMENT_KDE4;
            return DESKTOP_ENVIRONMENT_KDE3;
        }

        return DESKTOP_ENVIRONMENT_OTHER;
    }

    const char* GetDesktopEnvironmentName(DesktopEnvironment env)
    {
        switch (env) {
        case DESKTOP_ENVIRONMENT_OTHER:
            return NULL;
        case DESKTOP_ENVIRONMENT_GNOME:
            return "GNOME";
        case DESKTOP_ENVIRONMENT_KDE3:
            return "KDE3";
        case DESKTOP_ENVIRONMENT_KDE4:
            return "KDE4";
        case DESKTOP_ENVIRONMENT_KDE5:
            return "KDE5";
        case DESKTOP_ENVIRONMENT_UNITY:
            return "UNITY";
        case DESKTOP_ENVIRONMENT_XFCE:
            return "XFCE";
        }
        return NULL;
    }

    const char* GetDesktopEnvironmentName(Environment* env)
    {
        return GetDesktopEnvironmentName(GetDesktopEnvironment(env));
    }

} // namespace nix
} // namespace base
